After years of federal review, there was little question last year that construction of the pipeline, which would transport heavy, oil-like bitumen from Alberta to the Gulf of Mexico coast, should proceed. Thousands of miles of pipeline already crisscross this country. An environmental analysis had concluded that the risks of adding this new stretch were low. An economic review had found that Canada would get its bitumen to the world market — if not via pipeline to the gulf, then very likely by ship to China. Supply would make it to demand, one way or another.

Environmentalists nevertheless made Keystone XL a rallying issue. Among other things, they pointed to disquiet in Nebraska about the pipeline’s proposed route, objecting that it would traverse environmentally sensitive areas, such as the state’s Sand Hills. Under pressure from Nebraska’s government, would-be pipeline builder Trans­Canada began looking at altering the route. In the meantime, facing a congressionally mandated deadline, the Obama administration rejected TransCanada’s application, citing the Nebraska routing question. Mr. Obama left open the possibility of approving a fresh application that, conveniently, would come after the presidential election.

The election is past, TransCanada has reapplied with a new proposed route, and this week Nebraska Gov. Dave Heineman (R) signed off on the plan, following an analysis from the state’s Department of Environmental Quality. The regulators found that the new route would avoid the Sand Hills and other areas of concern. Though there is always some risk of spill, they said, “impacts on aquifers from a release should be localized, and Keystone would be responsible for any cleanup.” TransCanada will have to buy at least $200 million in insurance to cover any cleanup costs.

Unfortunately, when Mr. Obama rejected the Keystone XL application last year, that also halted the federal regulatory process, and those cogs will take a while longer to start turning anew. The State Department, which has jurisdiction, has said it expects to have a decision in the first quarter of this year.

Mr. Obama should ignore the activists who have bizarrely chosen to make Keystone XL a line-in-the-sand issue, when there are dozens more of far greater environmental import. He knows that the way to cut oil use is to reduce demand for the stuff, and he has begun to put that knowledge into practice, setting tough new fuel-efficiency standards for cars and trucks. That will actually make a difference, unlike blocking a pipeline here or there.